Collapsible packaging sleeve

ABSTRACT

This invention relates to a collapsible packaging sleeve made of a foamed polyolefin material such as polypropylene. The sleeve may be formed from one or more sheets of material joined into a continuous ring, or it may be assembled from separable sleeve parts. The collapsiblity is provided by the removal of material from the sheet(s) to create a recess within the sheet defining a region of reduced thickness. When bent about the region of reduced thickness, the material undergoes the well-known transformation known as “whitening”, enabling it to perform repeated hinging movements.

FIELD OF THE INVENTION

[0001] This invention relates to a collapsible packaging sleeve.

BACKGROUND TO THE INVENTION

[0002] When products are being transported, for example between a manufacturer and a customer, it is known to load them into a pallet, the pallet having standardised dimensions and being of a form suitable for being picked up and moved by a forklift truck and other materials handling equipment. Such palletised transportation is used for a very wide range of products, from foodstuffs to motor parts, for example.

[0003] Some pallets are rigid-sided, and these pallets suffer from the major disadvantage that they occupy the same volume when empty as they do when full. Thus, when such pallets are being returned to the manufacturer there is a significant cost penalty as the shipper is mainly transporting air.

[0004] To reduce this problem, collapsible pallets have been created, and one design of such pallet has a preformed base part and top part, and a sleeve providing the sides. The sleeve is separable from the base part and the top part, and is also collapsible so that when the pallet is empty the sleeve can be laid substantially flat together with the base part and top part and occupy only a small proportion of the volume of the erected pallet. When erected, the sleeve is located and held in place by the base part and top part.

[0005] In a first type of collapsible pallet, the sleeve is a single component which when erected forms a continuous ring of rectangular form, matched to the desired dimensions of the pallet. A second type of collapsible pallet utilises a sleeve made from two separate parts, the sleeve parts being preferably substantially identically formed as two “L”-shaped parts which can be placed together to form a ring of rectangular form.

[0006] The first type of pallet is advantageous for loose and substantially non-rigid products. The second type of pallet is advantageous for certain packaged products, particularly for packaged products which are themselves substantially rigid (such as packs of sugar or margarine, for example). With such packaged products, one of the L-shaped sleeve parts can be fitted to the base part of the pallet, and the products loaded from the side, the second L-shaped sleeve part only being added when the pallet is full or partly full. The first type of sleeve is less desirable in such applications because it requires all of the products to be loaded into the pallet from the top.

[0007] The size of the erected pallet is determined by the standards set by the materials handling industry. The erected pallet must be sufficiently strong to retain the products therein, and must also be sufficiently rigid to be liable to stacking. Accordingly, the materials from which the pallet base part, top part and sleeve can be made are limited. It is also desirable that the materials from which the pallet is made be sufficiently durable to be able to withstand repeated use, so that the pallet becomes reusable. Such re-use reduces the wastage of material, and also reduces the elemental cost of the palletised packaging in the product cost.

[0008] It has been suggested to use a plastics material such as polypropylene for the sleeve, but this material is relatively heavy (having a specific gravity of 0.92). Other materials have therefore been developed, including “CONPEARL” (T.M.), available from Fredola of Germany. “CONPEARL” comprises two layers of a plastics material separated by an intermediate corrugated layer. The structure is therefore somewhat similar to double-faced corrugated paper or cardboard, and the benefits of increased structural rigidity and low weight are shared by this material.

[0009] However, “CONPEARL” is not a food grade material, i.e. the sleeves of “CONPEARL” cannot be used for pallets which are to transport foodstuffs, since the spaces within the material might trap dirt and/or water. In addition, the material does not itself fold or hinge, so that separate means need to be provided to allow the sleeve to hinge between its collapsed and erected states.

[0010] The method of adding a foaming agent into a plastics material, so that the resulting material has a less dense structure, is well known and used for many different types of plastics materials. It is also possible to produce foamed polypropylene, such material being manufactured by Roechling Plastics of Haren, Germany, and sold under the trade name “FOAMLITE”. “FOAMLITE” has a specific gravity of 0.69, and is a food grade material.

[0011] Whilst “FOAMLITE” is suitably lightweight to be used as a material for making packaging sleeves, it has not previously been possible to use this material for such purpose, and packaged foodstuffs have heretofore typically been loaded onto pallets and secured thereon by shrink-wrap plastics materials; the present invention discloses a collapsible packaging sleeve which is manufactured from “FOAMLITE”, or another suitable foamed polyolefin, i.e. polyethylene.

SUMMARY OF THE INVENTION

[0012] According to the invention, there is provided a packaging sleeve manufactured from one or more sheets of a foamed polyolefin material.

[0013] Preferably, the polyolefin material is polypropylene. In a first embodiment of packaging sleeve, the sleeve forms a continuous ring, and is desirably manfactured from a single sheet of material, the ends of the sheet being bonded together. Alternatively, more than one sheet may be used, the ends of adjacent sheets being bonded together to provide a continuous sleeve.

[0014] A second embodiment of packaging sleeve is assembled from at least two separable parts, the sleeve including interconnection means by which the sleeve parts may be releasably connected together to form a ring.

[0015] Desirably, each separable part is substantially “L”-shaped. Preferably, the sleeve part is its erected state comprises a long side portion, an end portion and a short side portion, the end portion being substantially perpendicular to, and being joined to, both of the side portions. When assembled into a sleeve comprising two such sleeve parts, the long side portion of the first part is substantially coplanar with the short side portion of the second part, and the short side portion of the first part is substantially coplanar with the long side portion of the second part.

[0016] Desirably, a short side portion and a long side portion together define the longer side edge of the erected sleeve, and the end portions comprise the shorter side edges of the erected sleeve.

[0017] Usefully, the combined length of the short side portion and the end portion is less than the length of the longer side edge of the erected sleeve. This permits the sleeve part in its collapsed state to lie within the area of the base part and top part. Preferably, when collapsed the angle of the hinge between the short side portion and the end portion will be close to zero, whilst the angle of the hinge between the long side portion and the end portion will be close to 180°.

[0018] Preferably, the interconnection means joins the short side portion of one sleeve part to the long side portion of the other sleeve part. Preferably also, the interconnection means comprises a pair of substantially flat strips secured to opposed sides of one of the side portions of a sleeve part, the panels projecting beyond the end of the side portion and providing a channel into which the other cooperating side portion can be fitted.

[0019] The interconnection means is desirably substantially permanently connected to one of the cooperating side portions. The interconnection means may be heat-welded or chemically bonded to a side portion, for example.

[0020] Preferably, an interconnection means is secured to each of the sleeve parts; in embodiments having two sleeve parts these parts can be substantially identical. Preferably also, in embodiments having sleeve parts of L-section, the interconnection means is secured to the long side portion. This latter feature has the advantage that the interconnection means can serve to strengthen the long side portion and make this less liable to flexure or bowing under load, it being understood that the long side portion is more liable to such flexure than the short side portion.

[0021] Usefully, the hinges or fold-lines of the material are provided by the removal of substantially linear sections of material to provide a recess in the sheet. For example, with a sheet of material 6 mm or 8 mm thick, enough material could be removed to leave only a 1-2 mm wall section.

[0022] Desirably, the recess created by the removal of material has angled sides, preferably angled at between 40° and 50°, and ideally angled at approximately 45°.

[0023] Desirably also, the recess has a substantially flat bottom, the flat bottom having a lateral extent desirably between 1 and 5 mm, and usefully between 1.5-2 mm. Importantly, the junction between the sides of the recess and the bottom thereof should be curved, having a radius of curvature of at least approximately 1 mm, and ideally around 2 mm.

[0024] A 90° corner in the erected sleeve may be provided by one or two hinges or fold-lines; in the latter embodiments the two recesses are created close together. In the collapsed state certain of the four corners will be required to bend through approximately 180°, and the provision of two hinges or fold lines for each corner reduces the strain on each hinge during collapsing movement. Alternatively stated, it may be desired that each hinge move through a maximum angle of approximately 90°, and this maximum is utilised only in the collapsed state. Desirably, in those embodiments having two hinges for each corner the recesses for each corner are separated by a distance of 10 mm or less, and ideally by a distance around 0.5 mm greater than the thickness of the sheet.

[0025] It has been realised that the form of the recesses is critical to the effectiveness of the material as a packaging sleeve, and the form described above has been found to be successful—collapsing of the sleeve (and folding of the hinges) invoking the automatic response known with such materials to change their structure locally to provide a hinge able to undergo repeated hinging movements. The change of structure is accompanied by a “whitening” of the material adjacent the hinge, as will be recognised by those skilled in this art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

[0027]FIG. 1 shows a schematic exploded view of a pallet comprising a base part, a continuous sleeve, and a top part;

[0028]FIG. 2 shows a perspective view of a continuous sleeve according to the invention, the sleeve being in a partly collapsed state;

[0029]FIG. 3 shows an end view of the fully-collapsed sleeve of FIG. 2;

[0030]FIG. 4 shows an end view of a part of the sleeve of FIG. 2, adjacent a pair of recesses;

[0031]FIG. 5 shows an end view of a corner of the sleeve of FIG. 2, in the erected state;

[0032]FIG. 6 shows an end view of a corner of the sleeve of FIG. 2, in the collapsed state;

[0033]FIG. 7 shows a schematic exploded view of a pallet comprising a base part, a second embodiment of sleeve according to the invention, and a top part;

[0034]FIG. 8 shows a plan view of the sleeve of FIG. 7 in the erected and assembled condition;

[0035]FIG. 9 shows an enlarged view of one of the connections between the two sleeve parts of FIG. 1;

[0036]FIG. 10 shows a detailed view of a recess created in a sleeve part of FIG. 7 to form a hinge or fold-line therein; and

[0037]FIG. 11 shows an end view of a sleeve part of FIG.7, in the collapsed state.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0038]FIG. 1 shows a standard (prior art) pallet 10 comprising a base part 12, a top part 14 and a sleeve 16. As will be undertood by those skilled in this art, the base part is sufficiently rigid to support the weight of the loaded pallet (and also the weight of additional pallets stacked on top of this pallet), and has formations (not shown) to enable it to receive the forks of a fork lift truck. In addition, the top part is adapted to withstand the weight of additional pallets stacked on top of this pallet, and has formations (not shown) which can cooperate with the formations upon the base of an additional pallet. In certain designs, the form of the base part 12 and the top part 14 are identical.

[0039] The base part 12 and the top part 14 have corresponding flanges 18 which in the assembled pallet surround the bottom and top respectively of the sleeve 16, and help to locate the sleeve.

[0040] The form of the base part 12 and the top part 14 are not important to the present invention, and so the detailed form of these parts is not shown, nor need be described further.

[0041] The sleeve 16 is of a known material such as “CONPEARL”, and is adapted to collapse (into a similar collapsed state as shown in FIG. 3). In this way, the collapsed pallet comprising the base part 12, top part 14 and collapsed sleeve 16 can be transported in a reduced volume

[0042] A first design of packaging sleeve 20 according to the invention is shown in FIGS. 2-6. FIG. 2 shows the sleeve in a partly-collapsed state. Each corner 22 is formed from a pair of identical fold-lines 24. Also, adjacent the centre of each of the opposed side walls 26 another pair of fold-lines 28 provides a side hinge 30, enabling the side walls 26 to fold inwardly as shown.

[0043] The sleeve 20 is formed from two substantially identical sheets of “FOAMLITE” foamed polypropylene (though in other embodments foamed polyethylene could alternatively be used), respective ends of the sheets being joined together at conventional weld-lines 32 so as to provide a continuous sleeve.

[0044] It will be observed that the weld-lines 32 are offset from the centres of each of the side walls 34, and this is to enable one or both of the side walls 34 to accommodate a door or other means of allowing access into the pallet other than through the top. Thus, some customers require a door or pivotted flap to be provided in one of the side walls to permit access to the pallet e.g. without needing to remove the top part 14, and this can readily be accommodated in sleeves according to the invention.

[0045] In other embodiments, the sleeve 20 can be manufacured from a single sheet (requiring only a single weld line), from two dis-similar sheets, or from more that two sheets (requiring three or more weld lines), as desired.

[0046] In addition, certain customers have particularly formed base parts and top parts, and require the sleeves to have castellations or other formations along their top edge 36 and/or bottom edge 38; such formations can readily be provided in the original sheet or sheets from which the sleeve is manufactured.

[0047] The collapsed state of the sleeve 20 is shown in FIG. 3. In this state, each of the corners 22 is folded through approximately 180°, and each side hinge 30 is also folded through approximately 180° (though in the opposite sense), so that the respective parts of the sides 26, and the sides 34, lie in a parallel plane. The overall volume occupied by the collapsed sleeve, comprising the product of the dimensions of a side wall 34 and the height h of the collapsed sleeve, is reduced considerably over the volume of the erected sleeve.

[0048] The form of the recesses 40 which provide the fold lines 24, 28 is shown in FIG. 4. The thickness of the sheet of material is T (in this embodiment 6 mm), and each recess removes material to leave a resulting thickness t (in this embodiment 1.5 mm). The bottom of each recess is substantially flat for a lateral extent w (in this embodiment 2 mm), and the angle of each side of the recess is α (in this embodiment 45°, though in other embodiments suitably between 40° and 50°). In addition, the junction between the sides of the recess and the bottom thereof is curved, the radius of curvature r (FIG. 10) being a minimum of 1 mm.

[0049] Such a recess has been found to enable the sheet to be folded through approximately 90° and create a “white” hinge, i.e. the structure of the polypropylene material is changed adjacent the hinge to provide a hinge capable of repeated operation, as will be understood by those skilled in this art.

[0050] Since in the collapsed state each corner 22 and each side hinge 30 must fold through approximately 180°, a pair of recesses 40 are provided for each corner and for each side hinge, the recesses in each pair being separated by a distance s. In this embodiment the distance s is r approximately 10 mm, but since this distance has a direct bearing upon the collapsed height h, it is possible that this distance be reduced, ideally so that the surface 42 of the sheet between the recesses is approximately 0.5 mm greater than the thickness T.

[0051] It will be understood that sleeves of foamed polypropylene are flexible and resilient, and that when several collapsed sleeves are placed one on top of another they will become compressed further than the “flat sheet” condition shown in FIG. 3; FIG. 3 therefore represents the somewhat artificial condition of all of the sheets of the sleeve being totally flat and all of the corners and side hinges being exactly 180°, and the collapsed sleeve occupies its maximum possible volume. In practice, however, some flexibility of the sheets, and some non-uniformity of the angles, would likely occur to reduce the volume of the collapsed sheet beyond that shown in FIG. 3, i.e. the angle of each corner can exceed 180° because of the inherent flexibility and resilience of the material.

[0052] It will be understood that in this embodiment the recesses 28 for each side hinge 30 are formed in the opposite side of the sheet to the recesses 24 for the corners 22, since the sleeve folds in a different direction at the side hinges than it does at the corners. However, this is optional since the sheet can be folded in either direction around the hinges.

[0053]FIG. 5 shows a corner 22 in the erected state of the sleeve. In this state, the angle undertaken by each fold-line will be approximately equal and approximately 45°, with the surface 42 therefore lying at approximately 45° to the sheet either side of the corner. It is an additional advantage of this sleeve construction that the angled corner which results from two fold-lines 24 makes it easier to fit the sleeve into the base part 12 and the top part 14.

[0054]FIG. 6 shows the corner 22 in the collapsed state of the sleeve, with both of the corners 24 being approximately 90°, and the surface 42 also lying at approximately 90° to the sheet either side of the corner.

[0055] In the second embodiment of pallet 110 shown in FIGS. 7-11, the sleeve 116 comprises two identical sleeve parts 120, which are each of substantially “L”-shape in plan view, comprising a long side portion 122, a short side portion 124, and an end portion 126 which lies between and is joined by a hinge or fold-line to both of the side portions.

[0056] Each sleeve part 120 carries an interconnection means 130, which is better seen in FIG. 9. In this embodiment the interconnection means comprises two strips 132 of sheet-like material which are secured to the long side portion 122 of each of the sleeve parts 120. The strips 132 are secured to the long side portion 122 by linear welds 134, though in alternative embodiments the strips may be spot-welded or chemically bonded to the long side portion 122, or substantially permanently secured thereto by any suitable means.

[0057] The strips 132 project beyond the end of the long side portion 122, and the gap between the projecting strips forms a channel 136 into which a part of the short side portion 24 of the other sleeve part 120 can be fitted. It will be understood that the short side portion 124 can slide relatively freely into and out of the channel 136, and also slide relatively freely along the channel 136; thus, there is no requirement for the short side portion to be “clamped” or otherwise fixed to the long side portion 122 since when the pallet is erected the base part 12 and the top part 14 will ensure that the side portions are maintained substantially together, and all that is required of the interconnection means 130 is that relative lateral movement between the respective side portions is minimised or prevented, as might otherwise occur if the palletised product shifts during transportation.

[0058] In the embodiment shown, the sleeve parts 120 and the strips 132, are formed from foamed polypropylene material having a similar thickness; in this embodiment the sheet thickness T (FIG. 4) is 8 mm. Clearly, other thicknesses of both the sleeve parts 120 and the strips 132 could be provided as desired for the particular application, and it is not necessary that the thickness of the strips 132 match the thickness of the sleeve parts 120.

[0059] In the application shown it is desired that the channel 136 have a depth d of approximately 30 mm, i.e. almost four times the thickness T of the sheet. Also, it is desired that the length l (by which the strips 132 overlap the long side portion 122 to which they are secured) be approximately 20 mm. The exact dimensions 1 and d in relation to the sheet thickness T would be chosen to suit the particular application; however, it is desired that the dimensions d and 1 be minimised so as to reduce the weight of the sleeve parts 120.

[0060] It would clearly be possible to affix two interconnection means 130 to one of the sleeve parts, with the other sleeve part carrying no interconnection means. However, it is preferred that each sleeve part carry one interconnection means, and that all sleeve parts carry the interconnection means at the same location, so that any sleeve part 120 can be used with any other sleeve part 120 and the maintenance of the sleeve parts in matched pairs is not required. It is preferred that the interconnection means be secured to the long side portion 122 of each sleeve part 120, for two main reasons. Firstly, when assembling the two erected sleeve parts together it is easier to manipulate the short side portion 124 to fit within a channel carried by the long side portion 122, than it would be to manipulate the long side portion 122 to fit within a channel carried by the short side portion 124. Secondly, when under load (as for example when an erected pallet has other erected pallets stacked thereonto) the long side portion is more likely to flex or bow than the short side portion, and the securement of the interconnection means to the long side portion reduces the likelihood of such flexure or bowing.

[0061] Alternative interconnection means could clearly be provided by which the two sleeve parts could be interconnected. One such alternative would be a separate extruded component 138 as shown in FIG. 11. The interconnection component 138 is of substantially “H” cross-section, the cross-bar of the “H” being adapted to lie between the edges of the respective side portions, with the arms of the “H” forming channels for the respective edges. Preferably, an interconnection component 138 is substantially permanently secured to each of the sleeve parts 120, and desirably the long side portion 122 thereof, to be retained therewith.

[0062] The interconnection component 138 could be welded or adhered to one of the side portions, but alternatively could be provided with barbs so that when it was forced over the end of a side portion it could not easily be removed therefrom. The interconnection component 138 could be made as an extruded component, and could be of a different material than the sleeve parts 120.

[0063] As above indicated, each sleeve part 120 is preferably formed from a single sheet of material. In order to allow the material to he folded into the desired L-shape, recesses such as those shown at 140 in FIG. 10 are made to provide hinge or fold-lines therein.

[0064] One particular form of recess 140 is shown in FIG. 10. In this embodiment the sides of the recess are angled at an angle α, in this embodiment of 450 (though angles between 40° and 50° are also believed to be acceptable). The bottom of the recess 140 is substantially flat for a width w of approximately 4 mm. The junction of the sides of the recess and the bottom of the recess is curved, having a radius of curvature r of approximately 2 mm. The remaining wall section adjacent the recess has a thickness t of less than 2 mm, preferably between 1.2 and 1.4 mm, in this embodiment 1.3 mm. The above dimensions have been found to work satisfactorily, though it is expected that small changes in significant an effect upon the utility of the resulting sleeve part. In particular, two parallel recesses having the dimensions of FIG. 4 could be used with the second embodiment, and the single recess having the dimensions of FIG. 10 could be used with the first embodiment. However, it has been found that a single recess cannot reliably be hinged through 180° if the recess faces inwardly, i.e. the use of a single recess is limited to those embodiments such as shown in FIG. 11 in which the sheet is arranged so that the recess which requires hinging through 180° faces outwardly. If, as in the embodiment shown, a single recess 140 b is used for a corner which will have to hinge through 180° in the collapsed condition, it is desirable to have a greater width w than is required for each of two parallel recesses such as those of FIG. 4.

[0065] It is another benefit of a corner formed from two parallel recesses that it can reliably and repeatedly be hinged through 180° in either direction, i.e. the recesses can face inwardly or outwardly in the collapsed condition. This has a particular advantage in the first embodiment of sleeve 20 since notwithstanding that in the collapsed condition the hinges 22 and 30 are folded through 180° in opposite directions, the recesses 40 can all be cut into the same side of the sheet, reducing the time and therefore cost necessary to manufacture the sleeve. It will be appreciated that the recesses 140 a, b of the embodiment of FIG. 11 are also cut into the same side of the sheet and so share this manufacturing advantage.

[0066] The collapsed sleeve 120 is shown in FIG. 11. When in its collapsed state, it is preferred that the hinge line formed by the recess 140 a between the short side portion 124 and the end potion 126 be flattened out and that the hinge line formed by the recess 140 b between the end portion 126 and the long side portion 122 be folded further (i.e. the angle between the short side portion 124 and the end portion 126 should be approximately 0°, whilst the angle between the end portion 126 and the long side portion 122 should be approximately 180°). The advantage of such an arrangement lies in the ability of the collapsed sleeve part 120 to lie within the area of the base part 12 and the top part 14. If, for example, the erected pallet has dimensions X=1200 mm and Y=1000 mm (FIG. 7), the long side portion could have a length l₁ of 1050 mm and the short side portion a length l₂ of 150 mm (FIG. 8); the end portion would have a length approximately equal to the dimension Y (1000 mm).

[0067] When collapsed as shown in FIG. 11, the combined length of the end portion 126 and the short side portion 124 would be approximately 1150 mm, whilst the length of the long side portion 122 would be approximately 1080 mm (i.e. the length l₁ plus the depth d of the channel 136). Both of these dimensions are less than 1200 mm. It will be arranged that the height h (FIG. 1) of the erected sleeve is less than 1000 mm, so that the collapsed sleeve parts 20 can lie within the area of the base part 12 and the top part 14, and ideally can lie inside the flange 18, so minimising the collapsed volume.

[0068] In the erected state the recesses 140 preferably face towards the outside of the sleeve 116, though it will be understood that the hinges will operate effectively if the recesses face inwardly or outwardly. Facing the recesses outwardly produces a more defined corner on the inside of the sleeve 116 (maximising the volume within the sleeve), and also acts to “round” the outside of the corners. This latter feature has the advantage of easier fitment into the base part 12 and top part 14, which parts typically have channels (not shown in the schematic representation of FIG. 1 or FIG. 7) formed therein to receive and locate the bottom and top of the sleeve respectively. Since the corners of these channels are typically not a perfectly defined 90° corner, the rounding of the sleeve outer periphery more closely matches the actual shape of the channel and facilitates easier location of the sleeve within the base part and top part.

[0069] The resulting pallet has the major advantage that it Is of food-grade material, and so can allow the palletisation of foodstuffs which could previously only be packed by shrink-wrapping or the like. It will be understood that shrink-wrapped foodstuffs cannot be stacked on top of similarly-packaged products. With the present invention, however, it is envisaged that up to three erected and filled pallets could be stacked, giving a potential three-fold increase in container utilisation. 

1. A collapsible packaging sleeve manufactured from one or more sheets of a foamed polyolefin material.
 2. A packaging sleeve according to claim 1 in which the polyolefin material is polypropylene.
 3. A packaging sleeve according to claim 1 in which the sleeve is manfactured from a single sheet of material, the ends of the sheet being bonded together to provide a continuous ring.
 4. A packaging sleeve according to claim 1 in which the sleeve is assembled from at least two separable sleeve parts, the sleeve including interconnection means by which the sleeve parts may be releasably connected together to form a ring.
 5. A packaging sleeve according to claim 4 in which each sleeve part is substantially “L”-shaped in its erected condition.
 6. A packaging sleeve according to claim 5 in which each sleeve part is its erected condition comprises a long side portion, an end portion and a short side portion, the end portion being substantially perpendicular to, and being joined to, both of the side portions.
 7. A packaging sleeve according to claim 6 in which a short side portion of a first sleeve part and a long side portion of a second sleeve part together define the longer side edge of the erected sleeve, and the end portion of each sleeve part comprises a shorter side edge of the erected sleeve.
 8. A packaging sleeve according to claim 6 in which the combined length of the short side portion and the end portion of each sleeve part is less than the length of the longer side edge of the erected sleeve.
 9. A packaging sleeve according to claims 6 in which when each sleeve part is collapsed the angle of the hinge between the short side portion and the end portion will be close to zero, whilst the angle of the hinge between the long side portion and the end portion will be close to 180°.
 10. A packaging sleeve according to claim 6 in which the interconnection means joins the short side portion of a first sleeve part to the long side portion of a second sleeve part.
 11. A packaging sleeve according to claim 6 in which the interconnection means comprises an extruded component.
 12. A packaging sleeve according to claim 1 in which the collapsibility is provided by hinges in the material, and in which each hinge is defined by the removal of a linear section of material to provide a recess in the sheet.
 13. A packaging sleeve according to claim 12 in which the recesses for all of the hinges of the sleeve are formed in the same side of the sheet.
 14. A packaging sleeve according to claim 12 in which the sheet of material is between 6 mm and 8 mm thick, and in which the hinges are defined by the removal of linear sections of material to provide a recess of a depth sufficient to leave a remaining thickness of between 1 and 2 mm.
 15. A packaging sleeve according to claim 12 in which the recess has angled sides.
 16. A packaging sleeve according to claim 14 in which the sides of the recess are angled at between 40° and 50°.
 17. A packaging sleeve according to claim 12 in which the recess has a substantially flat bottom, the flat bottom having a lateral extent of approximately 1.5-5 mm.
 18. A packaging sleeve according to claim 12 in which the junction between the sides of the recess and the bottom of the recess is curved.
 19. A packaging sleeve according to claim 17 in which the junction has a radius of curvature of at least 1 mm.
 20. A packaging sleeve according to claim 12 in which a 90° corner in the erected sleeve or sleeve part is provided by a single recess.
 21. A packaging sleeve according to claim 12 in which a 90° corner in the erected sleeve or sleeve part is provided by two parallel recesses close together.
 22. A packaging sleeve according to claim 21 in which the recesses for each 90° corner are separated by a distance of 10 mm or less.
 23. A packaging sleeve according to claim 21 in which the recesses are separated by a distance around 0.5 mm greater than the thickness of the sheet. 